The invention concerns a device for transporting sticky and/or wet material in a horizontal direction. Such devices are known and are often used for transporting sludge such as sewage sludge with a dry matter content of 20-30%. The known devices have the disadvantage that if the trough is filled to a too high level the sticky and/or wet material often moves back through the opening in the centre of the shaftless spiral or screw and so limits the capacity of the device.